JP 2010-151053 A (PTL 1) discloses an invention of a fuel injection nozzle. The fuel injection nozzle achieves both atomization of fuel spray and controllability of an injection direction by having a flared nozzle hole formed to face outwardly on a downstream side and by allowing a relation between a distance x and a length L to satisfy x/L<0.05, where the distance x is between a portion of an upstream end face of the nozzle hole farthest from a central axis and a portion of a downstream end face of the nozzle hose nearest the central axis and the length L is a length of a wall surface of the nozzle hole on the central axis side.
JP 2001-317431 A (PTL 2) discloses an invention of a fluid injection nozzle. The fluid injection nozzle achieves atomization of fuel spray by having nozzle holes disposed to be spaced away from a central axis of a nozzle plate toward a fuel injection direction and thereby allowing fuel that flows in the nozzle hole to be guided along, and spreading over, an inner peripheral surface of the nozzle hole before being injected as a liquid film.
JP 2008-169766 A (PTL 3) discloses an invention of a fuel injection nozzle that has eighteen nozzle holes that are formed in a nozzle plate and divided into two groups. In the fuel injection nozzle, the two groups of nozzle holes form spray flows extending in two directions. The fuel injection nozzle forms spray flows such that intersection points between imaginary straight lines that represent passage axes of the respective nozzle holes extending in the fuel injection direction and an imaginary plane that is a predetermined distance away in the fuel injection direction from the nozzle hole plate and that is orthogonal to an injection axis of the nozzle hole plate are disposed at vertices of a regular octagon.